Adjustable vacuum switch



Jan. 3, 1967 R. w. FRASER 5 5 ADJUSTABLE VACUUM SWITCH Filed June 12, 1964 Robes? W Fraser,

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United States Patent 3,296,395 ADJUSTABLE VACUUM SWITCH Robert W. Fraser, Framingham, Mass, assignor to United-Carr Incorporated, Cambridge, Mass, a corporation of Delaware Filed June 12, 1964, Ser. No. 374,628 1 Claim. (Cl. 200-83) This invention relates generally to switches and more specifically to a switch actuated by a vacuum.

An object of the present invention is to provide a switch which will close a circuit when a vacuum has reached a predetermined level of vacuum condition.

Another object of the present invention is to provide a switch which may be adjusted for a predetermined vacuum condition without dismantling the switch.

A further object of the present invention is to provide a vacuum switch wherein a flexible diaphragm reacts to the changes of pressure in a vacuum and forces a movable contact into engagement with an adjustable second contact.

In the drawings:

FIG. 1 is a schematic representation partly in section showing a vacuum cleaner chamber utilizing the switch of the invention;

FIG. 2 is a top plan view of the switch with the diaphragm and cover plate removed;

FIG. 3 is a bottom plan view of the switch shown in FIG. 2 with the insulating cover removed;

FIG. 4 is a bottom plan view of the switch;

FIG. 5 is a section taken on lines 5-5 of FIG. 4 with the diaphragm and movable contact in neutral position; and

FIG. 6 is a section similar to FIG. 5 partially in elevation showing the diaphragm and movable contact actuated.

In the drawings, there is shown a switch 10 which is connected by a lead 12 to a socket 14 and a lead 15 which is connected to the indicator light 16. The socket 14 in turn is connected by a second lead 13 to the indicator light 16 and it is also connected to a plug (no number) having leads which ultimately go to a source of electrical power. The socket 14 is formed of insulating material, and, in this particular case, utilizes a snap in groove type engagement with the vacuum chamber housing 18. The vacuum chamber housing 18 has an intake opening 20, which is attached by means well known in the art to a porous bag 22. There is also formed through the housing 18 directly across from and in line with the intake opening 20 an exhaust opening 24. Directly in front of and in close proximity to the exhaust opening 24, a fan 26 is mounted on a motor 28. The fan 26 is preferably mounted within an inner housing 30, which has an opening in it on the same line as the intake and exhaust openings. In other words, the inner housing 30 places the fan 26 within a separate compartment from the remaining portion of the area defined by the vacuum chamber housing 18.

The switch 10 comprises a housing 32 formed of an insulating material including a base portion 34, an inner upstanding circumferential wall 35, an outer circumferential wall 36 connected to the upper surface of said inner wall by a connector portion 37. The connector portion 37 is on a plane in substantially spaced parallel relationship to the plane of the base portion 34. The outer wall 36 is in spaced circumscribing relationship with the base portion 34 and the inner wall 35 as shown in FIG. 5. It also has a free edge extending beyond the plane of the base portion 34. An internal circumferential shoulder 38 is formed in the inner wall 35 spaced from the base portion 34.

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The base portion 34 and the inner wall 35 define a Well 40. A leaf spring contact 42 formed of an electrically conductive material is riveted to the base portion 34 and has bends formed in it whereby the major portion of the spring contact 42 is spaced from the base portion 34 in substantial parallel relationship therewith. The base portion 34 has an aperture 44 formed therethrough which is continued as a chamber 47 and then a channel or bore 46 of a nozzle 48. The nozzle 48 extends from and is integral with the opposite side of the base portion 34 from the attachment of the leaf spring contact 42. An internally threaded bushing 54 is attached through a hole in the base portion 34 and an external screw like contact 50 is threaded into the internally threaded bushing 54 to lie in spaced relation and directly below the spring contact 42 as indicated in FIG. 5.

When the leaf spring contact 42 is riveted to the base portion 34, the same rivet is utilized to hold a ring terminal 52 on the opposite side of the base portion 34. The internally threaded bushing 54 includes a head portion and a tubular shank. A second ring terminal 56 is placed around the shank of the bushing 54 adjacent its head portion and then the bushing 54 is passed through a hole in the base portion 34 and curled over to complete the engagement therewith. Thus, in the disclosed construction there is a ring terminal on each side of the nozzle 48 as shown in FIG. 3 and FIG. 5. The slotted head of the screw like contact 50 is faced toward the same plane as that toward which the nozzle 48 is directed. A rubber diaphragm 58, formed of a highly flexible material, in this case rubber, and having a circular configuration is placed to cover the well 40 with the peripheral ridge of the diaphragm 58, which is formed of a thicker material than its center portion, resting on the internal circumferential shoulder 38. The diaphragm 58 seals the well 40 from direct contact with its environment for a purpose to be set forth hereinafter. The top plane of the peripheral ridge of the diaphragm 58 lies on the same plane as the top surface of the housing 32 of the switch 10. The more flexible center portion of the diaphragm 58 is spaced below the upper surface of the ridge and the upper surface of the housing 32 as shown in FIG. 5. A pair of wing like extensions 60 are formed by the outer wall 36 and the connector portion 37 on each side of the housing 32. Each of the wings 60 has an aperture formed through its portion of the connector portion 37. A cover plate 62 formed of cold rolled steel is placed over the housing 32 in superposed abutting relation to the ridge of the diaphragm 58 and the extensions 60. An aperture is formed through each of the wings, which extends from the cover plate 62 and the configuration of the cover plate 62 is the same as the external configuration of the top surface of the housing 32. An air vent 64 is formed centrally in the cover plate 62 as indicated in FIG. 5. On the opposite side of the base portion 34 from the leaf spring contact 42 an insulating cover 66 is provided having a configuration which is the same as the bottom surface of the housing 32. The nozzle 48 has two portions, the first which is adjacent to the base portion 34, referred to hereinbefore as the chamber 47, has greater internal and external diameters than the remaining portion of the nozzle 48. An aperature is provided in each of the wings of the insulating cover 66 and a large aperture is formed axially in the insulating cover 66 so that the outer surface of the wall of the chamber 47 of the nozzle 48 can be passed therethrough. A small adjustment aperture 70 is formed in close proximity to the centrally located hole of the insulating cover 66 and is placed so as to be directly over the head of the screw like contact 50.

When the insulating cover 66 and the cover plate 62 are both in place on the housing 32, a through hole is provided in each wing of the assembly. An eyelet can now be passed through the apertures and the terminal ends of the eyelet curled over to hold the switch in assembly.

The exemplification in FIG. 1 will be utilized to illustrate one way in which the switch 10 may be utilized. When a clean porous bag 22 has been placed over the intake opening of the vacuum chamber housing 18 and the fan 26 is caused to rotate, air will be drawn both from the vacuum chamber and through the porous bag 22, which tends to create a vacuum in the vacuum chamber housing and within the bag 22. As the bag 22 fills with debris, less air will be drawn from the outside through the bag 22 and more air will be drawn from within the vacuum chamber housing 18 thus increasing the vacuum. This increase in the vacuum will also increase the vacuum in the larger chamber 47, the well 40 and the channel of the nozzle 48, which protrudes into the vacuum chamber as shown in FIG. 1. Since the air pressure above the diaphragm 58 is maintained at the same level as that of the outside air through the utilization of the air vent 64, and that area is isolated from the vacuum itself, this pressure will force the diaphragm 58 down against the spring contact 42 causing it to flex toward the screw like contact 50, The contact 50 may be adjusted through the adjustment aperture 70 with a screwdriver to a predetermined vacuum condition within the vacuum chamber housing 18. When the required vacuum condition is reached, the spring contact 42 will engage against the screw like contact 50 causing the circuit to be completed and the indicator light 16 to glow informing the housewife that the bag 22 has been filled.

While there has been illustrated and described a preferred embodiment of the invention, it should be understood that the invention is best defined by the following claim.

What is claimed:

A vacuum switch comprising a housing formed of insulating material, said housing including a circumferential wall defining a tubular well, having a circumferential shoulder portion formed therein and having a base portion and an opening, an aperture formed through said base portion, a tubular nozzle extending from said base portion, having a channel extending therethrough, said channel forming a continuation of said aperture, a movable leaf spring contact and an adjustable second contact each extending into said well, said movable contact and said second contact spaced from each other and a flexible diaphragm lying completely within said well and having portions in abutting relationship with said circumferential shoulder, and a vented cover plate mounted on said housing above and abutted to said diaphragm to hold said diaphragm in position, said diaphragm having a planar, uninterrupted center portion including an under surface and being in spaced relation to said base portion and to said movable contact, and covering the major portion of the opening of said well whereby an increase in a vacuum connected to said nozzle will cause said under surface of said diaphragm to deflect said movable contact toward 7,

said second contact.

References Cited by the Examiner UNITED STATES PATENTS 2,253,629 8/ 1941 Kupferschmid 200-83 2,294,031 8/ 1942 Hobbs et al.

2,343,545 3/1944 Ford et al. 200-83 X 2,697,766 12/1954 Goldmutz 200-83 X 2,822,530 2/1958 Roten 200-83 X 3,049,603 8/ 1962 Flatt et al. 200-83 3,116,382 12/1963 Loomis et al 200-83 BERNARD A. GILHEANY, Primary Examiner. H. M. FLECK, G. MAIER, Assistant Examiners. 

